This disclosure relates generally to near-eye-displays, and in particular, to waveguide displays including 2-dimensional (2-D) scanners.
In conventional display designs in near-eye-displays, the factors considered are brightness, resolution, and compactness. Typical MEMS scanners use a collimated laser beam for scanning which can be high power and have a good efficiency to be directed to image location, and the image can be as bright as needed. While laser-based MEMS scanners are compact, they have issues with resolution.
Mirror size and resonance frequency are two fundamental limits for resolution. In the far-field, mirror size determines the diffraction spread angle of the scanned laser beam. A large mirror is required to have a smaller diffraction spread angle. The resonance frequency determines how many lines can be scanned in a vertical (slow-axis) direction. Accordingly, a high resonance frequency is desired to generate more scan lines. When the mirror is made larger, its resonance frequency is always smaller. Typical MEMS scanners are unable to scan more number of lines with a large mirror due to this trade-off between mirror size and resonance frequency.